Question

朋友你好我正在开发应用程序，其中视图有一个textField＆amp; 2个按钮。当用户单击“添加”时，文本字段中的文本应存储在datatabse中。当用户单击“显示”时，从数据库中提取的数据应显示在textField中。编写的代码就像这样

//SettingsApplicationViewController.h

#import "FMDatabase.h"

@interface SettingsApplicationViewController : UIViewController {

    FMDatabase *db;

    IBOutlet UITextField *urlField;

    IBOutlet UIButton *insertButton;

    IBOutlet UIButton *displayButton;

}

@property(nonatomic, retain) IBOutlet UITextField *urlField;

@property(nonatomic, retain) IBOutlet UIButton *insertButton;

@property(nonatomic, retain) IBOutlet UIButton *displayButton;

-(void)insertButtonClicked :(id)sender;

-(void)displayButtonClicked:(id)sender;

-(id)initApp;


@end

//  SettingsApplicationViewController.m

    #import "SettingsApplicationViewController.h"
#import "FMDatabase.h"

@implementation SettingsApplicationViewController


@synthesize urlField;

@synthesize insertButton;

@synthesize displayButton;

-(id)initApp

{

    if(![super init])
        return nil;

    //DB stored in application bundle
    NSString *DBName = @"SettingDB.sqlite";
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *path = [documentsDirectory stringByAppendingString:DBName];

    db = [FMDatabase databaseWithPath:path];
    [db setLogsErrors:TRUE];
    [db setTraceExecution:TRUE];

    if(![db open])
    {
        NSLog(@"Could not open Database");
        return 0;
    }

    else
    {
        NSLog(@"Database opened successfully");
    }
    return self;
}


    - (void)viewDidLoad {
    [super viewDidLoad];
    [self initApp];
}


    -(void)insertButtonClicked :(id)sender
{

[db executeUpdate:@"insert into Settings values (?)",urlField.text];
    [self resignFirstResponder];

}

    -(void)displayButtonClicked:(id)sender

{

    NSString *returnResult = [[NSString alloc]init];
    FMResultSet *rs = [db executeQuery:@"select url from Settings"];
    while ([rs next])
    {
        returnResult = [rs stringForColumn:@"url"];
        [urlField setText:returnResult];
    }


}

// SettingDB.sqlite

CREATE TABLE Settings(url text(50));

我在IB＆amp;复制了libsqlite3.dylib＆amp; FMDatabase文件。我不知道为什么“＃”没有打印在这篇文章中，但我的代码中有＃。

编译此代码时，显示如下错误

Command /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/gcc-4.2 failed with exit code 1

请帮帮我朋友。感谢

Answer 1

当您在Xcode中引用文件且该文件不在上述路径中时，通常会显示此错误。（该文件将在Project Navigator中显示为红色）

Answer 2

您是否为这些按钮分配了操作？

如果不这样做，

而不是-(void)insertButtonClicked :(id)sender;使用-(IBAction)insertButtonClicked :(id)sender;并将它们分配给相应的按钮操作。

或者，

在viewdidLoad中，

[insertButton addTarget:self action:@selector(insertButtonClicked:)   forControlEvents:UIControlEventTouchUpInside]; 
[displayButton addTarget:self action:@selector(displaytButtonClicked:)   forControlEvents:UIControlEventTouchUpInside];

SQLite示例应用程序

2 个答案: